It has been my experience that neither social background nor education has any real impact on intelligence. One’s occupation does not seem to predict their intelligence either, though performance in any occupation does. Of course, how long a particular occupation will retain someone of high IQ definitely depends on how interesting that person finds the work and that is quite unpredictable. And, some occupations will be quite limiting for someone without a high enough IQ to perform. For example, you don’t find many theoretical physicists with an IQ below 120 though they do come in a wide range of social skill.

Since education, social class and most other environmental factors seem not to have any real effect on IQ, an assertion based only on personal experience, it seems quite reasonable to look for genetic markers. And, since no race is excluded from producing brilliant people those genetic markers must be more basic to humans than are the markers for race. I think the search for such genes is well worth the effort. Note however, that being born with particular traits cannot be blamed entirely on genes. It seems that a great deal of what we are born with is a matter of chance. I’m not even implying environment during development, but rather just chance. I suspect you are born with a particular IQ or g for the same reasons you are born with particular fingerprints.

If I’m right, then a more important question is how to educate people so that we, and they, get the most from what they are born with. I think “no child left behind” should be replaced with “no child’s potential left underdeveloped”.

-Troy Stark

One is a study of SNPs with no proven chemical effect on anything, and thus no meaningful conclusion can be drawn from them. For all we know, they are intron polymorphisms (the paper fails to specify!), in which case it’s absurd to link them to anything behavioral.

The other is a meta-analysis, enough said. If I had a dollar for every time some statistical hand-waving allowed a meta-analysis to reach an opposite conclusion from every other study on the same topic, I’d be wealthy enough to pay poor kids to write this comment for me. From the perspective of scholarship, they are not worth much. Double so in the case of biology or medicine.

Also both articles beg the question they seek to discover, namely whether “intelligence” is a meaningful description of human behavior. In general, studies on this topic consistently fail to eliminate sufficient variables from environment to make a meaningful conclusion about a genetic basis for variations in intelligence, not including obvious cases of mental retardation or Down syndrome or something like that. The “in otherwise healthy adults” category still supports a null hypothesis.

i think the question is how we could objectively average variables without even controlling them par avance, as seems to be the case with ‘intelligence’.
could there be such a thing as global intelligence which can be measured by IQ, i highly doubt it.

even if IQ marks were 100% accurate, how could we possibly differentiate genetic factors from environment ones which affect different parts of IQ?

Intelligence and genes is certainly a case in point.

First, Carl Zimmer never answers the question why the brain in the first place.

All organic life is cognitive because it is a Responsive Design. Carl Zimmer is still on the shore where Evolution is guided by Darwinian conception through Natural Selection, saying nothing!

Roy D. Schickedanz
Refuting Charles Darwin in the case of Life’s Responsive Design

It is notable that some transgenic manipulations of mice result in animals that exhibit greater intelligence in some behavioral tests. Some of these are pretty crude manipulations, such as deleting or overexpressing a particular gene, so it seems unlikely that the apparently greater intelligence results in a benefit in a natural environment–if it did, the mutation would likely already be common. Very likely the improved intelligence in some contexts is associated with deficiencies in behaviors that are not tested in the laboratory. However, it supports the common wisdom that intelligence is multifactorial, and cannot be adequately defined by a single score.

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2265649
https://oa.doria.fi/bitstream/handle/10024/33645/searchfo.pdf?sequence=1

It would be nice to have another summary of the all the researches that look at environmental factors that influence IQ. viz.,
- Parental economic conditions
- Parental verbal ability
- Food habits
- Temperate/Tropical environment